Holes are usually countersunk when installing what?

Countersinking refers to the process of creating a conical hole that allows the head of a screw to sit flush with or below the surface of the material it is being driven into. This is particularly common for flat-head screws, which are designed with a flat underside that sits against the material when fully installed.

When flat-head screws are used, countersinking is essential because it helps reduce the potential for snagging or damage to other components, and it provides a more aesthetically pleasing finish. This is important in applications where the surface needs to remain smooth or when it is expected that the surface interacts with other parts.

In contrast, other types of screws such as hex screws, round-head screws, and set screws have different head designs which may not require or benefit from countersinking. Hex screws typically have a cylindrical head that stands proud, while round-head screws also sit above the surface due to their rounded shape. Set screws are generally installed to sit below the surface of the material but are intended to be used without countersinks. Thus, the usage of countersinking is specifically tailored to enhance the functionality and appearance of flat-head screws.